Individual Differences And Family Resemblances In Animal Behavior - A Study Of Habit Formation In Various Strains Of Mice

INDIVIDUAL DIFFERENCES AND FAMILY RESEMBLANCES IN ANIMAL BEHAVIOR A STUDY OF HABIT FORMATION IN VARIOUS STRAINS OF MICE - CONTENTS I . Historical ......................................... 1 I1 . Statement of the Prdblem ............................ 3 I11 . Methods of the Experiment .......................... 4 IV . Tests of Learning Ability ............................ 6 a In the Maze .................................... 6 b In the fultiple Choice Apparatus ................ 6 V . Experimental Results ............................... 9 a Time and Error Averages for all Tests ............ 9 b Difference in Learning between Families of White and Yellow Mice .............................. 9 c Results for faze Test ........................... 11 1 The Initial Learning ........................ 11 2 The Interference ........................... 17 3 The Retention ............................. 18 d Results for Multiple Choice Test .................. 20 V1 . Correlations in Learning Records between a Time and Error ................................ 23 b Performance at Beginning and End of Tests ....... 24 c Initial Learning Records and Retention ........... 24 d Performance in Maze Test with Performance in Mul-tiple Choice Test ............................. 25 V11 . Family Resemblances ............................... 26 Mean Variations for Related and Unrelated Individuals . . 27 V111 . Sex Differences .................................... 29 a Differences in Time and E m r Records ............ 29 b Comparative Distributions of the Males and Female a 30 c VariabiIity of the Sexes ......................... 33 IX . Individual Differences and Methods of Habit Formation . . 36 X . Health Conditions andLearning Ability ............... 42 XI . Family Histories ................................... 44 XI1 . Summary and Results ............................... I. HISTORICAL IN the present thesis an effort has been made to combine in a single study three main points of investigation first, the genetic study of behavior secondly, the subject of individual merences and thirdly, a consideration of the exact method of habit formation employed by the mice that have been tested in the experiments that are now to be reported. Practically no experimental work has been done upon individual differences and family resemblances in animal behavior. In most cases, the behaviorist has been content to study the mass reaction of a group of animals to external stimuli, and in the main, has not attempted to treat the variability of his group because of the relatively small number of animals tested. Professor J. McKeen Cattell, about fifteen years ago, began to apply the methods of genetics to the study of conduct, but the results obtained by him and his students were not published, and the problem has been given to me. Yerkes devotes a chapter of his book on The Dancing Mouse, to dserences in behavior, and there brings together results for variability in . . . general behavior, rapidity of learning, memory, and discrimination. His results showed the existence of a considerable amount of individual differences in the behavior of, the dancing mouse, and no family resemblan. ce in the litters he obtained...